Clayey silt reservoirs bearing natural gas hydrates (NGH) are considered to be the hydrate-bearing reservoirs that boast the highest reserves but tend to be the most difficult to exploit. They are ...proved to be exploitable by the first NGH production test conducted in the South China Sea in 2017. Based on the understanding of the first production test, the China Geological Survey determined the optimal target NGH reservoirs for production test and conducted a detailed assessment, numerical and experimental simulation, and onshore testing of the reservoirs. After that, it conducted the second offshore NGH production test in 1225 m deep Shenhu Area, South China Sea (also referred to as the second production test) from October 2019 to April 2020. During the second production test, a series of technical challenges of drilling horizontal wells in shallow soft strata in deep sea were met, including wellhead stability, directional drilling of a horizontal well, reservoir stimulation and sand control, and accurate depressurization. As a result, 30 days of continuous gas production was achieved, with a cumulative gas production of 86.14 ×104 m3. Thus, the average daily gas production is 2.87 ×104 m3, which is 5.57 times as much as that obtained in the first production test. Therefore, both the cumulative gas production and the daily gas production were highly improved compared to the first production test. As indicated by the monitoring results of the second production test, there was no anomaly in methane content in the seafloor, seawater, and atmosphere throughout the whole production test. This successful production test further indicates that safe and effective NGH exploitation is feasible in clayey silt NGH reservoirs. The industrialization of hydrates consists of five stages in general, namely theoretical research and simulation experiments, exploratory production test, experimental production test, productive production test, and commercial production. The second production test serves as an important step from the exploratory production test to experimental production test.
The hierarchical aggregation of molecular nanostructures from multiple components is a grand synthetic challenge, which requires highly selective linkage control. We demonstrate how two orthogonal ...linkage groups, that is, organotin and lanthanide cations, can be used to drive the aggregation of a giant molecular metal oxide superstructure. The title compound {(Sn(CH3)2)2O4{CeW5O18 TeW4O16CeSn(CH3)24TeW8O314}2}46− (1 a) features dimensions of ca. 2.2×2.3×3.4 nm3 and a molecular weight of ca. 25 kDa. Structural analysis shows the hierarchical aggregation from several independent subunits. Initial biomedical tests show that 1 features an inhibitory effect on the proliferation of HeLa cells based on an apoptosis pathway. In vivo experiments in mice reveal the antiproliferative activity of 1 and open new paths for further development of this new compound class.
Hierarchical assembly of a giant heterometallic polyoxotungstate supercluster with a molecular weight of ca. 25 kDa is reported. Geometrically unrestricted cerium(III) and geometrically restricted dimethyl tin cation linkers are used to gain access to a giant molecular species featuring three different polyoxometalate building units. The compound demonstrates in vitro and in vivo antiproliferative activity against HeLa cervical cancer cell lines.
Quarantine and isolation measures urgently adopted to control the COVID-19 pandemic might potentially have negative psychological and social effects. We conducted this cross-sectional, nationwide ...study to ascertain the psychological effect of quarantine and identify factors associated with mental health outcomes among population quarantined to further inform interventions of mitigating mental health risk especially for vulnerable groups under pandemic conditions. Sociodemographic data, attitudes toward the COVID-19, and mental health measurements of 56,679 participants from 34 provinces in China were collected by an online survey from February 28 to March 11, 2020. Of the 56,679 participants included in the study (mean SD age, 36.0 8.2 years), 27,149 (47.9%) were male and 16,454 (29.0%) ever experienced home confinement or centralized quarantine during COVID-19 outbreak. Compared those without quarantine and adjusted for potential confounders, quarantine measures were associated with increased risk of total psychological outcomes (prevalence, 34.1% vs 27.3%; odds ratio OR, 1.34; 95% CI, 1.28-1.39; P < 0.001). Multivariable logistic regression analyses showed that vulnerable groups of the quarantined population included those with pre-existing mental disorders or chronic physical diseases, frontline workers, those in the most severely affected areas during outbreak, infected or suspected patients, and those who are less financially well-off. Complying with quarantine, being able to take part in usual work, and having adequate understanding of information related to the outbreak were associated with less mental health issues. These results suggest that quarantine measures during COVID-19 pandemic are associated with increased risk of experiencing mental health burden, especially for vulnerable groups. Further study is needed to establish interventions to reduce mental health consequences of quarantine and empower wellbeing especially in vulnerable groups under pandemic conditions.
A retrospective analysis of routine surveillance data involving children hospitalized in central Wuhan, China, for acute lower respiratory infection in early January 2020 revealed six cases of ...Covid-19. The authors report clinical characteristics of the children and laboratory data.
NRP1 as multifunctional non-tyrosine-kinase receptors play critical roles in tumor progression. MicroRNAs (miRNAs) are an important class of pervasive genes that are involved in a variety of ...biological functions, particularly cancer. It remains unclear whether miRNAs can regulate the expression of NRP1. The goal of this study was to identify miRNAs that could inhibit the growth, invasion and metastasis of gastric cancer by targeting NRP1 expression. We found that miR-338 expression was reduced in gastric cancer cell lines and in gastric cancer tissues. Moreover, we found that miR-338 inhibited gastric cancer cell migration, invasion, proliferation and promoted apoptosis by targeting NRP1 expression. As an upstream regulator of NRP1, miR-338 directly targets NRP1. The forced expression of miR-338 inhibited the phosphorylation of Erk1/2, P38 MAPK and Akt; however, the expression of phosphorylated Erk1/2, P38 MAPK and Akt was restored by the overexpression of NRP1. In AGS cells infected with miR-338 or transfected with SiNRP1, the protein levels of fibronectin, vimentin, N-cadherin and SNAIL were decreased, but the expression of E-cadherin was increased. The expression of mesenchymal markers in miR-338-expressing cells was restored to normal levels by the restoration of NRP1 expression. In vivo, miR-338 also decreased tumor growth and suppressed D-MVA by targeting NRP1. Therefore, we conclude that miR-338 acts as a novel tumor suppressor gene in gastric cancer. miR-338 can decrease migratory, invasive, proliferative and apoptotic behaviors, as well as gastric cancer EMT, by attenuating the expression of NRP1.
Bamboo represents the only major lineage of grasses that is native to forests and is one of the most important non-timber forest products in the world. However, no species in the Bambusoideae ...subfamily has been sequenced. Here, we report a high-quality draft genome sequence of moso bamboo (P. heterocycla var. pubescens). The 2.05-Gb assembly covers 95% of the genomic region. Gene prediction modeling identified 31,987 genes, most of which are supported by cDNA and deep RNA sequencing data. Analyses of clustered gene families and gene collinearity show that bamboo underwent whole-genome duplication 7-12 million years ago. Identification of gene families that are key in cell wall biosynthesis suggests that the whole-genome duplication event generated more gene duplicates involved in bamboo shoot development. RNA sequencing analysis of bamboo flowering tissues suggests a potential connection between drought-responsive and flowering genes.
The equiatomic CrMnFeCoNi high-entropy alloy (HEA) exhibits outstanding toughness and excellent strength-ductility combination at cryogenic temperatures. However, its strength is relatively low at ...room temperature. In order to strengthen this HEA, microalloying additions of 0.8 at.% Nb and C were made and its properties and microstructure evaluated. It was found that the microalloying resulted in the formation of carbide precipitates and a reduction of the grain size to ∼2.6 μm. As a result, the room-temperature tensile yield strength (732 MPa) of the microalloyed HEA is roughly double that of the base HEA (with a concomitant increase in the ultimate strength) while its ductility is maintained at a relatively high level (elongation to fracture of ∼32%). The strengthening is due to precipitation hardening from the nanoscale carbide particles and grain refinement.
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•Nanoscale NbC particles in CrMnFeCoNi were obtained by microalloying with Nb and C.•Yield stress of NbC-added CrMnFeCoNi HEA is roughly double that of the base HEA.•The ductility of NbC-added CrMnFeCoNi HEA is maintained at a high level (∼32%).•Strengthening is due to precipitation hardening and grain refinement.
Precise control of solid-state elastic waves' mode content and coherence is of great use nowadays in reinforcing mechanical energy harvesting/storage, nondestructive material testing, wave-matter ...interaction, high sensitivity sensing, and information processing, etc. Its efficacy is highly dependent on having elastic transmission channels with lower loss and higher degree of freedom. Here, we demonstrate experimentally an elastic analog of the quantum spin Hall effects in a monolithically scalable configuration, which opens up a route in manipulating elastic waves represented by elastic pseudospins with spin-momentum locking. Their unique features including robustness and negligible propagation loss may enhance elastic planar-integrated circuit-level and system-level performance. Our approach promotes topological materials that can interact with solid-state phonons in both static and time-dependent regimes. It thus can be immediately applied to multifarious chip-scale topological phononic devices, such as path-arbitrary elastic wave-guiding, elastic splitters and elastic resonators with high-quality factors.
Azvudine (FNC) is a nucleoside analog that inhibits HIV-1 RNA-dependent RNA polymerase (RdRp). Recently, we discovered FNC an agent against SARS-CoV-2, and have taken it into Phase III trial for ...COVID-19 patients. FNC monophosphate analog inhibited SARS-CoV-2 and HCoV-OC43 coronavirus with an EC
between 1.2 and 4.3 μM, depending on viruses or cells, and selective index (SI) in 15-83 range. Oral administration of FNC in rats revealed a substantial thymus-homing feature, with FNC triphosphate (the active form) concentrated in the thymus and peripheral blood mononuclear cells (PBMC). Treating SARS-CoV-2 infected rhesus macaques with FNC (0.07 mg/kg, qd, orally) reduced viral load, recuperated the thymus, improved lymphocyte profiles, alleviated inflammation and organ damage, and lessened ground-glass opacities in chest X-ray. Single-cell sequencing suggested the promotion of thymus function by FNC. A randomized, single-arm clinical trial of FNC on compassionate use (n = 31) showed that oral FNC (5 mg, qd) cured all COVID-19 patients, with 100% viral ribonucleic acid negative conversion in 3.29 ± 2.22 days (range: 1-9 days) and 100% hospital discharge rate in 9.00 ± 4.93 days (range: 2-25 days). The side-effect of FNC is minor and transient dizziness and nausea in 16.12% (5/31) patients. Thus, FNC might cure COVID-19 through its anti-SARS-CoV-2 activity concentrated in the thymus, followed by promoted immunity.
Ischemic stroke is the major type of cerebrovascular disease usually resulting in death or disability among the aging population globally. Oxidative stress has been closely linked with ischemic ...stroke. Disequilibrium between excessive production of reactive oxygen species (ROS) and inherent antioxidant capacity leads to subsequent oxidative damage in the pathological progression of ischemic brain injury. Acupuncture has been applied widely in treating cerebrovascular diseases from time immemorial in China. This review mainly lays stress on the evidence to illuminate the possible mechanisms of acupuncture therapy in treating ischemic stroke through regulating oxidative stress. We found that by regulating a battery of molecular signaling pathways involved in redox modulation, acupuncture not only activates the inherent antioxidant enzyme system but also inhibits the excessive generation of ROS. Acupuncture therapy possesses the potential in alleviating oxidative stress caused by cerebral ischemia, which may be linked with the neuroprotective effect of acupuncture.
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